# Math

posted by .

A semi-truck travels on a paved road for 2 hours at an average speed of 20 miles per hour faster than it travels on a dirt road. The time spent on the dirt road is 3 hours. If the entire trip is 200 miles, how fast is the truck traveling on the dirt road?

• Math -

Use d = r * t for both the paved and the dirt roads. Use x for the unknown speed on the dirt road.

For the paved road, use d1 (distance 1):
d1 = r * t
d1 = (x + 20) * 3
so
d1 = 3(x + 20)

For the dirt road, use d2 (distance 2):
d2 = r * t
d2 = x * 3
so
d2 = 3x

Also, you know that the distance traveled on the paved road, d1, and the distance traveled on the dirt road, d2, sum to 200 miles. Thus, you know:
d1 + d2 = 200

See if you can take it from there.

## Similar Questions

1. ### math

the el paso middle school girls baxketball team is going from el paso to san antonio for the texas state championship game.the trip will be 560 miles.their bus travels at an average speed of 60 miles per hour. estimate the distance …
2. ### physics repost

9)You are taking a road trip to the beach for Spring Break. You leave at 12:00pm. At 12:10 you stop for lunch 10 miles down the road. You get back on the road and travel 75 more miles and realize that you need to stop for gas. You …
3. ### math

A car travels along a straight road, heading east for one hour then traveling for thirty minutes on another road that leads northeast. If the car has maintained a constant speed of forty miles an hour, how far is it from its starting …
4. ### Mathematics

A rectangular garden 50 m long and 34 m wide is surrounded by a uniform dirt road. Find the width of the road if the total area of the garden and road is 540 m^2. Explain your solution
5. ### Advanced Algebra Honors

A rectangular garden 50 m. long and 34 m. Wide is surrounded by a uniform dirt road. Find the width of the road if the total area of the garden and road is 4292 m^2.
6. ### math

A boy travels on his bicycle at the rate of 6 miles per hour and his sister on hers at the rate of 5 miles per hour. They start at the same time and place and travel over the same road in the same direction. After traveling for 3 hours, …
7. ### VNS,Math

A man walked into the road at 4 miles per hour and returned over the same road at the rate of 3 miles per hour. If he completed the entire trip in 7/2 hours,how far in miles in to the roads did he walk?
8. ### math

Martin rides to Cambridge 30 miles away from home at the average rate of 10 miles per hour.He returns on a better road that is 50% longer where he can increase his rate by 100%.How much time does he save by taking the better road on …
9. ### Math 101

A bus traveled on a straight road for 3 h at an average speed that was 15 mph faster than its average speed on a winding road. The time spent on the winding road was 4 h. Find the average speed on the winding road if the total trip …
10. ### Math

Randy travels north on a road 1029 miles long and Marco is travelling south on the same road. Randy-45m/hr marco- 53m/hr. How many hours will it take for them to pass?

More Similar Questions